Field of the Invention
The present invention relates to a damping force controlling shock absorber, and more particularly, to a damping force controlling shock absorber which is capable of forming a hard passage through connection of disks where slits are formed, and is capable of generating a soft damping force by using four passages formed in compression and rebound stroke directions of a spool guide, thereby simplifying a passage structure, reducing production dispersion of shock absorbers, and increasing productivity of shock absorbers.
Description of the Related Art
In general, a shock absorber is installed in means of transportation, such as automobile or the like, and improves ride comfort by absorbing and damping a vibration or shock from a road surface during driving.
Such a shock absorber includes a cylinder and a piston rod installed to be compressible and extendable within the cylinder. The cylinder and the piston rod are installed in a vehicle body, wheels, or axles.
A shock absorber, a damping force of which is set to be low, can improve ride comfort by absorbing a vibration caused by unevenness of a road surface during driving. On the contrary, a shock absorber, a damping force of which is set to be high, can improve steering stability by suppressing a change in a posture of a vehicle body.
Therefore, there has been developed a damping force controlling shock absorber in which a damping force controlling valve capable of appropriately adjusting damping force characteristics is mounted on one side of the shock absorber, such that the damping force characteristics are appropriately adjusted to improve ride comfort or steering stability according to a road surface and a driving condition.
In general, such a conventional damping force controlling shock absorber has a structure to select a hard passage and a soft passage by selectively opening and closing a plurality of passages formed in a spool guide while changing a position of a spool.
That is, a hard damping force or a soft damping force may be selectively generated by selectively adjusting an opened/closed state of the hard passage and the soft passage formed in the spool guide.
However, in the conventional damping force controlling shock absorber, since the hard passage and the soft passage are individually formed by using the plurality of passages formed in the spool guide, the structure of the shock absorber becomes complicated and dispersion may occur during mass production. Due to the complicated structure, a manufacturing cost of the shock absorber may increase.
As the prior document related to the present invention, Korean Patent Application Laid-Open No. 10-1998-0002962 (Mar. 30, 1998) discloses a damping force controlling buffer valve.